Abstract: Drying technology of the natural gas pipeline is usually used in gas pipeline construction, which is mainly used to solve the problem of water accumulation in the pipelines. The dew point of high-purity nitrogen used in nitrogen replacement in natural gas pipelines is low. Thus, using the water adsorption ability of the low-dew-point nitrogen, it can reach the purpose of drying the pipelines during the nitrogen replacement. This article discusses the drying method for absorbing water in gas pipelines using low-dew-point nitrogen in ideal condition. And referring to the examples of pipeline drying replacement, correlative results are obtained by analyzing the experimental data.